580 EX II underexposes?

[Jamesino]

I've noticed that my 580 EX II with a Rebel XTi frequently underexposes the shots by 1/3 to sometimes 3/3 stops regardless if it's bounced or straight on. Is this a common occurrence? From searching around the net, I've read similar complaints.

Is this remedied simply by +1/3 or +2/3 the FEC?

[Weddingguy1]

I've noticed that my 580 EX II with a Rebel XTi frequently underexposes the shots by 1/3 to sometimes 3/3 stops regardless if it's bounced or straight on. Is this a common occurrence? From searching around the net, I've read similar complaints.

Is this remedied simply by +1/3 or +2/3 the FEC?

Yes . . just up the power. Usually needed if you are in a large area with little bounce back from close walls and ceilings.

[Obtong]

Hi. On my 30D I had to set the FEC to +1 to get properly exposed pictures. On my 5D I only need to set my FEC to +1/3. You will have to experiment and see what works best for your set up and also the kinds of pictures you typically take.

~Dom

[FlyingPhotog]

Boy there's a firmware fix just begging to happen, eh?

[cookey]

I also have the same problem with my 30D,usually up the power by 2/3.

[Curtis N]

Boy there's a firmware fix just begging to happen, eh?Don't hold your breath.

Think about it - I use a different FEC setting for fill flash (i.e. there's a significant ambient contribution) than for flash as the main light source.

0 FEC with E-TTL is somewhere in-between. Often too much for fill, not enough for flash only exposure.

Now perhaps E-TTL can be enhanced to do a better job of accounting for the ambient exposure, but the bottom line is, only the photographer knows how much flash he wants.

So, no matter how it's calibrated, a thinking photographer will still need to adjust FEC to account for the conditions and his lighting goals. A "firmware fix" wouldn't really make things easier.

[Wilt]

Now perhaps E-TTL can be enhanced to do a better job of accounting for the ambient exposure, but the bottom line is, only the photographer knows how much flash he wants.

So, no matter how it's calibrated, a thinking photographer will still need to adjust FEC to account for the conditions and his lighting goals. A "firmware fix" wouldn't really make things easier.


I still think Canon fundamentally messed up big time, in that a photo taken with ambient only light (on a tripod) will photograph brighter than the same scene photographed with ETTL-controlled flash. They should be the same brightness. And if you wanted 'fill' rather than main light from flash, then dial in FEC = -1EV

And then they tried to be consistent in their error by screwing up their built in photosensor-controlled exposure, too!

[FlyingPhotog]

I still think Canon fundamentally messed up big time, in that a photo taken with ambient only light (on a tripod) will photograph brighter than the same scene photographed with ETTL-controlled flash. They should be the same brightness. And if you wanted 'fill' rather than main light from flash, then dial in FEC = -1EV

And then they tried to be consistent in their error by screwing up their built in photosensor-controlled exposure, too!

You've explained the background thinking that generated my comment.

I just forgot the background, sorry. :oops:

[roszell]

I usually leave mine at +2/3 for bounce flash and adjust from there.